The document proposes developing a field-scale research facility to study the effects of sea level rise on freshwater bottomland hardwood forests. It outlines: 1. Taking a representative area of a freshwater tidal wetland and manipulating its water levels to gain data on ecosystem responses to sea level rise. 2. The facility will test the hypothesis that as sea levels rise and hydroperiods change, these wetlands will shift in type and previously non-tidal wetlands will become tidally influenced. 3. The objectives are to design water control structures, develop an operational plan, and produce a site plan for the research area located in a bottomland hardwood forest in South Carolina.

1. Development of a Field-Scale Research Facility to Assess the
Effects of Sea Level Rise on Freshwater
Bottomland Hardwood Forests
Hudson Adams, Riley Garvey, Alyssa Knight, Rachel Mordovancey,
Mattie Rourk, Alexa Schiazza
Clemson University, Clemson, SC
December 1, 2020

2. Outline
● Introduction
○ Background
○ Rationale
○ Objective(s)
○ Approaches
● Literature Review
● Materials and Methods
● Results
● Recommendations
● Acknowledgements

3. Introduction

4. Background
Role of Wetlands
● Wetlands provide many important ecosystem services
○ Improving and protecting water quality
○ Providing fish and wildlife habitats
○ Storing floodwater
● Wetlands are some of the most productive ecosystems
● The overall global wetland value was estimated to be around
47.4 trillion dollars per year

5. Background
Climate Impact on Wetlands
● Climate change, and the resulting sea level rise, affect the health and
functionality of tidal wetlands.
● Sea level rise causes the inundation and potential displacement of these
areas.
● Such stressors may disassemble the existing ecosystem of the wetland due
to loss of vegetation, loss of habitat, and biogeochemical changes in the
soil.
● Wetlands offer valuable ecosystem services such as erosion control,
bioremediation, and flood protection.
● It is important to be able to predict how these services and ecosystems will
be impacted as sea levels rise.

6. Background
Wetland Maps

7. Background
Project Scope
● Freshwater tidal wetlands are wetlands that are influenced by the tides but
do not suffer from saltwater intrusion.
● In the lowlands of South Carolina these are both common and more distant
from the coastline than expected in other areas due to the extremely
gradual elevation changes.
● There are two types of freshwater tidal wetlands, marsh and forest, with
the differences occurring due to the hydroperiod, or the period of time the
wetland is covered by water.
● Ecosystem services can be negatively impacted by environmental/climate
change, therefore it is important to monitor these changes.

8. Background
Facility Location
● Located in the Santee
Experimental Forest on
the East Branch of the
Cooper River
● Sites are bottomland
hardwood forest

9. Rationale
● The purpose of this project is to design a facility that shows how wetlands will respond
to expected future sea-level rise. Wetlands provide many ecosystem services such as
improving water quality and storing flood water. If rising sea level affects the way these
wetlands currently function, then we may lose some of those services.
● The models currently used to predict how ecosystem services will be affected by climate
change are not useful for this project, as freshwater tidal wetlands have not been
adequately studied.
● The idea to address this problem is to take a mesocosm that represents the larger
wetland, and manipulate its water level to gain critical data on which to base future
models.
● It was decided that a field research facility would more easily bring together all of the
biogeochemical features that are endemic to a wetland. Replicating these interworking
features in a lab facility would have been more costly and less representative of the
wetland.

10. Hypothesis to be tested through the use of the
designed facility:
As sea level rises and
hydroperiods change, these
wetlands will shift in type and
previously nontidal wetlands will
become tidally influenced.

11. Objectives
Mission
Design and model a field scale research facility to study the impact of
climate change on the ecosystem services provided by wetlands, in
particular, to determine the effects of sea level rise on the hydrologic regime
and biological makeup of a freshwater tidal wetland.
Specific Objectives
1. To design impoundment/control water structures and drainage
systems
2. To develop an operational plan
3. To develop a site plan for research site

12. Client Deliverables
1. Hydrogeomorphic Assessment – this is an integrated assessment of the land
resource data providing a basis for the site selection
a. A detailed analysis of the natural and man-made subcatchments within the
floodplain that could be the mesocosms. This analysis will focus on utilizing
the lidar data to delineate drainage areas and flow paths within the
floodplain.
b. This analysis will consider the current flow paths and hydrologic regimes.
2. Summary on the expected impacts of sea-level rise on the current hydrologic
regime
3. Facility Operational Plan
4. Site Plan

13. Approaches
Task 1
To determine
a site location
Task 2
To design the
facility

14. Task 1: To determine a site location
Sub-Tasks:
● To collect hydrological, Lidar, climate, and GIS data for the possible sites.
● To assess references, data, and similar project designs.
● To research sea-level rise modelling done by NOAA or another agency in the
Charleston area.
● To explore water containment and management methods for both options.
● To determine biodiversity of local flora within each option.
● To identify size requirements and necessary site boundaries for both
options.
● To choose an alternative to move forward into design.

15. Approaches
Site Option 1: Tidally Influenced Sub-Catchment Channel
● Put a weir in “Channel A” to divert
water to “Channel B”
● Put berm at tidally influenced
intersection of “Channel B”
● Use main channel water to flood
“Channel B” area
Site Plan Site Map

16. Approaches
Site Option 1: Tidally Influenced
Sub-Catchment Channel
A B C
C
A
B

17. Approaches
Site Option 2: Non-Tidal Controlled Rice Fields
● Retrofit existing berms in rice field
plot
● Install a pump from Nicholson
Creek to the chosen rice field plot
● Construct a weir on the opposite
site of the rice field to let water
escape when necessary
Site Plan Site Map

18. Approaches
Site Option 2: Non-Tidal
Controlled Rice Fields
A B C
C
A
B

19. Task 2: To design a facility
Sub-Tasks:
● To evaluate site planning considerations including site access, elevation, and wetland
impact.
● To examine possible methods of passive flow/filling.
● To identify needs to maintain a healthy ecosystem such as water retention rate.
● To determine what additional infrastructure such as water control structures, pipe
networks, pumps, and drainage systems will be required.
● To model hydrologic regimes and design plans by utilizing CAD, HEC-RAS, and SOLIDWORKS.
● To create a design plan draft.
● To develop a final site plan.
● To formulate a facility operations plan by determining how the water control system will
run.
● To assess the cost of the designed field research facility.

20. Pre-/post-development
modeling and structural
drawings
Developing tidal
regime and
operational plans
CAD site
development
Task Management
Team
We collaborated as a group on all aspects of
the project. To ensure that everything got
done, each group member was assigned a
different task to be in charge of:
● Hudson Adams
○ Structural Drawings using
SolidWorks
● Riley Garvey
○ Pre-development modeling using
HEC-RAS
● Mattie Rourk
○ Operational Plans
○ Literature Review
● Alyssa Knight
○ Developing tidal regime
○ Post-development modeling using
HEC-RAS
● Rachel Mordavancy
○ Site development using CAD
● Alexa Schiazza
○ PowerPoint Format

21. Ecology Climate
Science
Engineering
TFW research
center
Maximizing use
of existing
infrastructure
Efficiently
capturing and
manipulating
water flows
Diverse
assemblage of
endemic
species

22. Literature
Review

23. Literature Review
Site Hydrology
● Most of the soils have high surface runoff and low infiltration
rates.
● Average annual rainfall: 1370 mm
● The peak discharges for the Turkey Creek watershed:
○ 12.0 m3/s--2 year return period
○ 22.9 m3/s--5 year return period
○ 31.5 m3/s--10 year return period
○ 42.9 m3/s--25 year return period
○ 53.2 m3/s--50 year return period
○ 64.2 m3/s--100 year return period
● Vegetation: pine-hardwood forests.
● The area in the watershed lies 2 m-14 m above sea level.

24. Literature Review
Parameters
● Going forward with the design, the research parameters that the facility will be used
for are:
○ Vegetation response
■ which will monitor changes in vegetation structure, composition, and
productivity including photosynthesis and transpiration
○ Soil response
■ which will monitor changes in soil biogeochemistry such as redox
conditions, greenhouse gas emissions, carbon storage, nutrient cycling,
also soil microbiology
○ Hydrologic response
■ which will monitor changes in hydrology and water quality

25. Literature Review
Turkey Creek Water Table Data
We will use Turkey Creek
data in order to estimate
Nicholson Creek flows off a
relative size comparison
since they are both type 3
streams

26. Literature Review
Tidal Information
● High tide and low tide alternate
approximately every 6 hours each day
● Tides shift back about an hour every day
○ Example: 6:30 one day, and 7:30 the
next, etc.
● Estimate timing and inflow and outflow
rates based on Huger Creek tidal data

27. Literature Review
Sea Level Rise
How high should the water be
raised?
● The relative sea-level rise trend
in Charleston, SC is about 3.32
mm/year based on monthly
mean sea level data spanning
from 1901 to 2019.
● This was determined to be the
equivalent to a 1.09 ft sea level
rise over the span of 100 years.

28. Literature Review
Sea Level Rise

29. Literature Review
Mesocosm vs. Large-Scale Experiment
Large Scale Experiment:
● Displayed an increase in
temperature over time.
● An increase in dissolved oxygen
over time.
● Larger scale experiments are
harder to control.
Mesocosm Experiment:
● Became colonized by macrophytes
which caused shading.
○ Lower temperature over time.
● Mesocosms are often more
optimal as they are more
replicable and repeatable.
Both:
● Retain nutrients.
● Showed an increase in pH.

30. Literature Review
Mesocosm vs. Large-Scale Experiment
How does the complexity
of these two set-ups
compare?
Symbol Key:

31. Materials
and
Methods

32. Materials and Methods
Modeling
● To create location and watershed basin maps of the site using ArcGIS
● To measure site hydrologic features, specifically raised water levels, using HEC-RAS
● For site design and plan set development will be created using AutoCAD Civil3D
● To design and model hydraulic structures, such as a weir structure, using SolidWorks

33. Materials and Methods
Site Needs
● Existing Conditions Evaluation
● Grading Needs (Fill Soils)
● Pump
● Hydraulic Structure: Weir
● Site Access Stair
● Electrical Instrumentation (Beyond Scope of Design)

34. Results

35. Results
Site Selection
Channel Rice Field

36. Results
Site Existing Conditions Utilizing Lidar Data
● Elevation data for the site was acquired from NOAA as a lidar point cloud.
○ Utilized in GIS and HEC-RAS as a DEM
○ Utilized in C3D as a dynamic TIN Surface

37. Results
Site Existing Conditions Utilizing AutoCAD
Existing Slope ≅ 4:1

38. Results
Pre-Development Flow Model Utilizing HEC-RAS
● 1-year rain event
● Rice fields are naturally
flooded from large storm
events
○ after 3 hours of this
storm, the average water
depth on the site was 22
cm
● Berms are partially inundated
- creating the need for
increased height and proper
grading

39. Results
Grading Utilizing C3D
● Utilized C3D’s Feature Lines and Grading Creation Tools
● Created new design surfaces by pasting grading data into the
existing ground surface.

40. Results
Berm Grading Utilizing C3D
● Due to the deteriorated condition
of the berms, reinforcement and a
raised height is required.
● Berms will be 3’ top width with a
3:1 slope down to the existing
grade.

41. Results
Post-Development Flow Model Utilizing HEC-RAS
● Simulating 1 foot of sea level
rise
● The pump creates an inflow
to raise the water level to 1 ft
in a 6 hour period to reach
high tide
● The gate opens and releases
water to empty the field over
a 6 hour period to reach low
tide

42. Results
Site Layout
Utilizing C3D

43. Results
Flow Rate Estimation
● The flow rate was determined using the equation Q = V/t
● The volume was determined to be 64,984.33ft3 based on the area
calculated through CAD modeling and a 1 foot depth with a 3:1 slope on all
sides.
● The time was set to equal 21,600s in order to match a tidal regime of 6
hours.
● The flow rate was found to be 3.01cfs or 1350 GPM

44. Results
Spillway Grading Utilizing C3D
● The spillway is
designed to retain
the low tide water
level while the
hydraulic weir will
hold the high tide.
● 3:1 slope down
from berms and
2% down the
spillway through
the berms

45. Results
Spillway Stabilization
● Major storm events can lead to concentrated
runoff that can erode the spillway.
● Erosion can be prevented using:
○ Protective grass vegetation
○ An appropriately designed rock cover
○ Concrete or other erosion control
matting
● After major storm events, compacted soil
can be placed in the eroded spillway to
restore the normal embankment.

46. Results
Pump Station Location
● Because the site is
located in the
Nicholson Creek
flood plain, the pump
cannot be placed
within the wetland
area.
● The station will be
located off of
Summerhouse Road
adjacent to
Nicholson Creek

47. Results
Pump Station Site
Grading Utilizing AutoCAD
● The road grade will be extended by
15’ to provide a 15’ ⨯ 15’ flat surface
in order to place the pump station.
● Graded to the existing ground at 3:1
slope

48. Results
Cost Assessment-Grading
● A volume comparison surface was
created from the existing and modeled
future ground.
● The net fill volume was calculated to be
950.17 yd3
● At an estimated $20 per yd3, the total
cost of the fill soils would be
approximately $19,004.

49. Results
Pipe Alignment Utilizing AutoCAD
● HDPE pressure pipe will
be utilized to pump
water from Nicholson
Creek to the rice field
plot.

50. Results -Pipe Alignment Profile Utilizing AutoCAD
● In order to avoid the
ecological impact of
burying the pipe, it will
be run over the ground
on stilts supported by
pylons
● Because of the warm
climate of Huger, SC,
temperature related
deflections of the pipe
are of minimal concern.
● The pylons will be
supported with
compacted fill material.

51. Results
Pump Sizing
● Hazen Williams Equation:
Friction Losses
○ Flow Rate= 1350 gpm
○ Friction Coefficient, C=150
○ Suction Side:
■ 44 Linear Feet (LF)
of 8” pipe.
■ Equivalent Length of
62 LF
○ Discharge Side:
■ 351 LF of 6” pipe
■ Equivalent Length of
404.5 LF
Total Friction Losses in Suction
Side = 1.52 ft
Total Friction Losses in
Discharge Side = 40.3 ft
Increases in friction from the fittings are
accounted for in “Effective Pipeline Length”
or equivalent length of pipe based on the
predetermined K factor for the fitting.
● LE=(K’)(D)
● Project Pipeline includes:
○ 2 - 90° Elbows
○ 2 - 45° Elbow
○ 2 - 15° Elbows
● LE(suction)= 18 LF
● LE(discharge)= 53.5LF

52. Results
Pump Sizing
● Total Dynamic Head (TDH):
○ Equivalent height of the fluid to be pumped.
○ Determined by head loss changes in the pipe.
● Total Dynamic Suction Lift = 10.52 ft
○ 1.52 ft of friction loss
○ 9 ft of suction lift head loss
● Total Dynamic Discharge Head = 34.3 ft
○ 40.3 ft of friction loss
○ 6 ft of elevation head gain
TDH = 44.82 ft

53. Results
Pump Sizing
● The Net Positive Suction Head
Available (NPSHA) is used to ensure
the pump picked and its Net
Positive Suction Head Required
(NPSHR) at the desired flow rate is
suitable for the system.
● Suction Lift Head: 9 ft
● Absolute Pressure: 34 ft
● Vapor Pressure: 1.06 ft
● Friction Loss In Suction Lift: 1.52 ft
NPSHA=22.21 ft

54. Results
Pump Sizing

55. Results
Pump Selection
● At 1350 GPM and 44.8 ft TDH, a
Xylem e-XC Suction Split Case
Pump was chosen.
○ 8 1/16” Radial Impeller
○ 20 HP Baldor Motor
○ NPSHR = 15.3 ft

56. Results - Pump Selection

57. Results
Pumping Considerations
● Because there is 44 LF of suction
lift, a priming system should be
considered.
● Loss of prime can cause gas
accumulation to block flow in the
pump and lead to damage
● A priming valve would place the
suction line under vacuum and
relocate the lowest point of
pressure to the pump.
● This allows water to rise in the
suction line and maintain a primed
pump.

58. Results
Cost Assessment-Pump and Piping
● 351 LF of 6” HDPE Pipe
○ $8.50 /LF
■ $2,984
● 44 LF of 8” HDPE Pressure Pipe
○ $12 /LF
■ $528
● 6” Elbow Fittings (2):
○ $194 /Ea
■ $388
● 8” Elbow Fittings (4):
○ $500 /Ea
■ $2,000
● Xylem Pump with motor and baseplate assembly
○ Includes freight and startup
■ $25,000
● Q-VAC Priming Valve System
■ $50,000
● Pump RVSS Control Panel
■ $50,000

59. Results
Hydraulic Design Utilizing SolidWorks
● Using the equation for
determining the flow rate of
a rectangular contracted weir
the length of the weir was
calculated.
● Q was set to be 3.01cfs as
found solving for the flow
rate
● H was set to be 1 ft to match
with the expected rise in the
water level of the wetland.
● The length was found to be
approximately 1 ft

60. Results
Hydraulic Design Utilizing SolidWorks
● Design includes a gate on the weir
that is operated by a rack and
pinion system powered by a small
motor
● The gate will be operated on a time
schedule to simulate the coming
and going of the tide each day
● Motor will be mounted on top of
the frame
● A ½ horse power motor is a cheap
and efficient way to operate the
door and should be more than
strong enough to function properly

61. Results
Rack and Pinion System
● Pros: Easy to design, easy to
maintain
● Cons: If the rack is misaligned
it may damage the entire
gear box, Can be inaccurate if
a higher quality is not bought
and maintained but this is
not an issue for this project.

62. Results
Cost Assessment-Hydraulic Design
● ½ horsepower motor: ~$100.00
● Rack and Pinion: ~$75.00
● 4 inch square tubing: ~$90.00
● 12x18 1” sheet metal: ~$120.00 x 2
● Weir Structure: ~$2000.00
● Total Cost: ~$2,505

63. Results
Operational Plan: Facility Use
● Simulated high tide will occur when the water within the rice field reaches a height of 1ft.
● Simulated low tide will occur when the rice field has been completely drained of water (~0ft).
● Low tide and high tide will alternate every 6 hours based on tidal information.
○ Low tide: 9AM, 9PM
○ High tide: 3PM, 3AM
● Water addition will occur immediately following low tide
● Drainage will occur immediately following high tide
● Water will be pumped into the rice field and flow out of the rice field through the weir at the
same rate.
○ Flow Rate: 3.01 cfs

64. Results
Operational Plan: Maintenance
Rack and Pinion System:
● Maintenance once every 4 weeks
(about once a month)
● Lubricate rack and pinion
Pump:
● Maintenance once every 4 weeks
(about once a month)
● Clean the system
● Check during winter months for
freezing possibility
○ On days when temperature
drops below freezing, do not
turn pump on
Spillway:
● Regularly monitor spillway for
weeds, brush, or obstructions
● Check spillway after major storm
events to repair erosion

65. Results
Cost Assessment-Labor
Team Members:
Alexa, Alyssa, Hudson, Mattie, Rachel, and Riley
Pre-/post-development
modeling and structural
drawings
Developing tidal
regime and
operational plans
Team
CAD site
development
Task Hours
Meetings 210
PowerPoint 162
Paper 40
Operational Plan 8
Statistics 2
Calculations 10
SolidWorks 12
GIS/AutoCAD 27
HEC-RAS (pre + post) 20
Total Hours 81 hours / person
Total Cost $8,100 / person

66. Results
Overall Cost Assessment
● Grading: $19,004
● Pump & Piping: $131,400
● Hydraulic Design: $2,505
● Labor: $48,600
● Total Cost of Project: $201,509.00

67. Recommendations

68. Recommendations
● We recommend implementing site option 2 - non-tidal controlled rice fields
for the research facility, based on the criteria outlined in the results section
as well as field observations
● We recommend using a Xylem e-XC Suction Split Case pump
● We recommend utilizing a gate with a rack and pinion system on the weir

69. Recommendations
● We recommend modeling the design on EPA-SWMM, instead of HEC-RAS
● We recommend operating the system on a 6 hour tidal schedule
● We recommend servicing the pump and rack and pinion system once a
month
● We recommend turning off the system during freezing temperatures

70. TFW research
center
Ecology Climate
Science
Engineering

71. Acknowledgements
Sincerely,
Alexa, Alyssa, Hudson, Mattie,
Rachel, and Riley
Dr. Darnault,
Thank you for guiding us throughout this
project and giving us helpful feedback
on our presentation and paper.
Dr. Xiao,
Thank you for your help throughout the
project process and giving us helpful
feedback about our powerpoint.
Dr. Trettin,
Thank you for giving us the opportunity to
work alongside you to develop a field-scale
research facility to observe the effects
global warming, specifically sea level rise,
has on bottomland hardwood forests. We
hope this project helps you and the USDA
Forestry service devise a plan to
implement in the future.
Julie,
Thank you for showing us around both the
tidally influenced sub-catchment channel,
and the non-tidal controlled rice fields.
This site visit was extremely helpful in the
completion of our project design.

72. Thank
You!